Supplementation of diets forOreochromis niloticuswith essential oil extracts from lemongrass (Cymbopogon citratus) and geranium (Pelargonium graveolens) and effects on growth, intestinal microbiota, antioxidant and immune activities

Abstract

This study aimed to investigate the effects of dietary supplementation of lemongrass (Cymbopogon citratus) (LEO) and geranium (Pelargonium graveolens) (GEO) essential oils on growth, immunity, antioxidant responses and disease resistance of Oreochromis niloticus. Fish (3.04 ± 0.003 g) were fed the basal diet (G 1 ), or the basal diet supplemented with LEO at 200 and 400 mg kg −1 of the diet (G 2 and G 3 ), or GEO at 200 and 400 mg kg −1 of the diet (G 4 and G 5 ), respectively for 12 weeks. Growth indices and feed utilization were significantly improved with G 2 , G 3 and G 5 groups. Also, a significant increase in protein content of the whole body was recorded in all groups. G 2 and G 5 showed a significant rise of both catalase activity and reduced glutathione content with a significant incline in the MDA level. Lysozyme activity and total IgM levels were significantly increased in G 2 and G 5 groups. G 3 and G 5 groups had a significantly lower intestinal total bacteria, Coliforms, Escherichia coli and Aeromonas spp counts. Following challenge with A. hydrophila, all groups had a high survival rate. In conclusion, LEO and GEO could be a candidate dietary supplementation in fish improving growth performance, feed utilization, oxidative status, immune responses and disease resistance.

Assessment of dietary supplementation with galactomannan oligosaccharides and phytogenics on gut microbiota of European sea bass (Dicentrarchus Labrax) fed low fishmeal and fish oil based diet

“…Prebiotics, such as mannan oligosaccharides (MOS) and phytogenics have proved to be effective at modulating fish microbiota in several studies [64,18,46,56,65,12,61]. In the present study, allochthonous intestinal microbiota of sea bass fed GMOS diet, but not GMO-SPHYTO, showed reduced number of Gammaproteobacteria, mainly represented by the Vibrionales order.…”

“…Consistent with our results, Ran et al [65] tested the effects of a commercial blend of thymol and carvacrol essential oils in hybrid tilapia finding a reduction of E. coli/Coliform in the gut microbiota. Similarly, in another study in tilapia (Oreochromis niloticus), supplementation of diet with EOs from lemongrass, and geranium significantly decreased intestinal total bacteria, Coliforms, E. coli, and Aeromonas counts [12].…”

“…EOs are potent antimicrobial agents against different strains of pathogenic and food borne bacteria [45,43]. Therefore, due to their antibacterial activity, phytochemicals can exert a prebiotic-like effect modulating fish gut bacterial composition [46,12].…”

“…These negative-side effects reduce the capacity of enterocytes to absorb nutrients and can promote the translocation of indigenous or opportunistic bacteria, potentially pathogenic for the host [8,7]. In this context, there is an increasing interest in functional feeds containing selected additives that can help to prevent or mitigate the intestinal epithelium damage caused by extreme plant-based diet formulations [9][10][11][12][13]. Feed additives have quite diverse chemical natures and characteristics; they may be both, nutritive and non-nutritive ingredients and may interact with fish physiology by either direct or indirect mechanisms [14].…”

Efficacy assessment of commercially available natural products and antibiotics, commonly used for mitigation of pathogenic Vibrio outbreaks in Ecuadorian Penaeus (Litopenaeus) vannamei hatcheries

“…campbellii [24–26], exhibit immunostimulant properties [24, 27], and improve the nutritional and health state of shrimp [28, 29]. Similarly, essential oils have shown to have antimicrobial [30], antioxidant [31] and antifungal [32] properties, which can be an alternative to the use of additives and drugs in shrimp production [33]. Although the use of organic acids and essential oils in Ecuadorian hatcheries is relatively new, there is an increasing demand for their application as control strategies of bacterial diseases in shrimp hatcheries.…”